Ok, let's look at the first part:
At each level (excluding 1 obviously), total exp needed is calculated as [Total Exp] from previous level + [XP needed] for current level.
Examples:
Lv2 - 5 total exp = 0 total exp from previous level + 5 exp needed for lv2
Lv3 - 15 total exp = 5 total exp from previous level + 10 exp needed for lv3
and so on...
Now if we look at this part,
It follows the same principle;
Lv70 - 368m total exp = 298m total exp from previous level + 70m exp needed for lv70
Lv71 - 450m total exp = 368m total exp from previous level + 81m needed for lv71
Lv72 - 568m total exp = 450m total exp from previous level + 110m exp needed for lv72 *THIS IS WRONG* (450 + 110 = 560)
And from here, the trend continues in a different manner, total exp = total exp from previous level + exp needed for previous level (no longer current one)
Examples:
Lv73 - 679m total exp = 568m total exp from previous level + 110m exp needed for lv72 (no longer 73 like before)
Lv74 - 806m total exp = 679m total exp from previous level + 127m exp needed for lv73 (no longer 74 like before)
And to prove this, the fact is that lv1 does not need any exp (0) neither does lv90 (0). This is because, starting from lv72, something gets messed up and you the [XP needed] is no longer exp for this level, but for the next one.
At each level (excluding 1 obviously), total exp needed is calculated as [Total Exp] from previous level + [XP needed] for current level.
Examples:
Lv2 - 5 total exp = 0 total exp from previous level + 5 exp needed for lv2
Lv3 - 15 total exp = 5 total exp from previous level + 10 exp needed for lv3
and so on...
Now if we look at this part,
It follows the same principle;
Lv70 - 368m total exp = 298m total exp from previous level + 70m exp needed for lv70
Lv71 - 450m total exp = 368m total exp from previous level + 81m needed for lv71
Lv72 - 568m total exp = 450m total exp from previous level + 110m exp needed for lv72 *THIS IS WRONG* (450 + 110 = 560)
And from here, the trend continues in a different manner, total exp = total exp from previous level + exp needed for previous level (no longer current one)
Examples:
Lv73 - 679m total exp = 568m total exp from previous level + 110m exp needed for lv72 (no longer 73 like before)
Lv74 - 806m total exp = 679m total exp from previous level + 127m exp needed for lv73 (no longer 74 like before)
And to prove this, the fact is that lv1 does not need any exp (0) neither does lv90 (0). This is because, starting from lv72, something gets messed up and you the [XP needed] is no longer exp for this level, but for the next one.